Astronomy:CT Chamaeleontis
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Short description: Star in the constellation Chamaleon
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Chamaeleon |
| Right ascension | 11h 04m 09.0989s[1] |
| Declination | −76° 27′ 19.3269″[1] |
| Apparent magnitude (V) | 12.31 to 12.43[2] |
| Characteristics | |
| A | |
| Evolutionary stage | T Tauri star |
| Spectral type | K7 Ve[3] |
| Variable type | INB[2] |
| B | |
| Spectral type | M8–L0[4] |
| Astrometry | |
| Radial velocity (Rv) | 15.13±0.09[5] km/s |
| Proper motion (μ) | RA: −22.209±0.039[1] mas/yr Dec.: −0.175±0.035[1] mas/yr |
| Parallax (π) | 5.2144 ± 0.0211[1] mas |
| Distance | 625 ± 3 ly (191.8 ± 0.8 pc) |
| Position (relative to CT Chamaeleontis) | |
| Component | B |
| Epoch of observation | 2006–2007 |
| Angular distance | 2.670″ [4] |
| Position angle | 300.7° [4] |
| Observed separation (projected) | ~440 AU [4] |
| Details[4][6] | |
| A | |
| Mass | 0.796+0.015 −0.014 M☉ |
| Radius | 2.06±0.05 R☉ |
| Luminosity | 1.41+0.17 −0.16 L☉ |
| Surface gravity (log g) | 4.5+0.7 −1.2 cgs |
| Temperature | 4,402+151 −166 K |
| Age | 2±2[4] Myr |
| B | |
| Mass | 19±5[7] MJup |
| Radius | 2.2+0.81 −0.6 RJup |
| Luminosity | 0.002 L☉ |
| Surface gravity (log g) | 3.5 cgs |
| Temperature | 2,500±100[7] K |
| Age | 2±2[4] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
| B | |
CT Chamaeleontis (CT Cha) is a T Tauri star - a primary of the star system in the constellation of Chamaeleon.[8] It has an apparent visual magnitude which varies between 12.31 and 12.43.[2] The star is still accreting material at rate 6×10−10 M☉/year.[7]
Brown dwarf/Planetary system
A visual band light curve for CT Chamaeleontis, plotted from ASAS data[9]
In 2006 and 2007, a faint companion was observed 2.7 arcseconds away from CT Chamaeleontis, using the Very Large Telescope at the European Southern Observatory. Since the object shares common proper motion with CT Chamaeleontis, it is believed to be physically close to the star, with a projected separation of approximately 440 astronomical units. It is estimated to have a mass of approximately 17 Jupiter masses and is probably a brown dwarf or a planet.[4] The companion has been designated CT Chamaeleontis B.[10] The companion was proven to be most likely in the brown dwarf mass range in 2015.[7]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| protoplanetary disk | 6.1–9.3 AU | 54.0+1.0 −0.9° |
— | |||
| B | 19±5 MJ | 514 | — | — | — | — |
References
- ↑ 1.0 1.1 1.2 1.3 1.4 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G. Gaia DR2 record for this source at VizieR.
- ↑ 2.0 2.1 2.2 CT Cha, database entry, The combined table of GCVS Vols I-III and NL 67-78 with improved coordinates, General Catalogue of Variable Stars , Sternberg Astronomical Institute, Moscow, Russia. Accessed on line October 1, 2008.
- ↑ Torres, C. A. O.; Quast, G. R.; da Silva, L.; de la Reza, R.; Melo, C. H. F.; Sterzik, M. (12 September 2006). "Search for associations containing young stars (SACY)". Astronomy & Astrophysics 460 (3): 695–708. doi:10.1051/0004-6361:20065602. ISSN 0004-6361. Bibcode: 2006A&A...460..695T.
- ↑ 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 Schmidt, T. O. B.; Neuhäuser, R.; Seifahrt, A.; Vogt, N.; Bedalov, A.; Helling, Ch.; Witte, S.; Hauschildt, P. H. (2008). "Direct evidence of a sub-stellar companion around CT Chamaeleontis". Astronomy & Astrophysics 491 (1): 311–320. doi:10.1051/0004-6361:20078840. Bibcode: 2008A&A...491..311S.
- ↑ Nguyen, Duy Cuong; Brandeker, Alexis; van Kerkwijk, Marten H.; Jayawardhana, Ray (6 January 2012). "Close Companions to Young Stars. I. A Large Spectroscopic Survey in Chamaeleon I and Taurus-Auriga". The Astrophysical Journal 745 (2): 119. doi:10.1088/0004-637X/745/2/119. ISSN 0004-637X. Bibcode: 2012ApJ...745..119N.
- ↑ 6.0 6.1 Sheehan, Patrick D.; Wu, Ya-Lin; Eisner, Josh A.; Tobin, John J. (2019). "High Precision Dynamical Masses of Pre-Main Sequence Stars with ALMA and Gaia". The Astrophysical Journal 874 (2): 136. doi:10.3847/1538-4357/ab09f9. Bibcode: 2019ApJ...874..136S.
- ↑ 7.0 7.1 7.2 7.3 Wu, Ya-Lin; Close, Laird M.; Males, Jared R.; Barman, Travis S.; Morzinski, Katie M.; Follette, Katherine B.; Bailey, Vanessa; Rodigas, Timothy J. et al. (2015). "New Extinction and Mass Estimates from Optical Photometry of the Very Low Mass Brown Dwarf Companion CT Chamaeleontis B with the Magellan AO System". The Astrophysical Journal 801 (1): 4. doi:10.1088/0004-637X/801/1/4. Bibcode: 2015ApJ...801....4W.
- ↑ V* CT Cha -- T Tau-type Star, database entry, SIMBAD. Accessed on line October 1, 2008.
- ↑ "ASAS All Star Catalogue". The All Sky Automated Survey. http://www.astrouw.edu.pl/asas/?page=aasc.
- ↑ NAME CT Cha B -- Extra-solar Planet Candidate, database entry, SIMBAD. Accessed on line October 1, 2008.
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